The present invention relates to the art of hanger supports for suspending heavy objects such as ceiling fans, light fixtures and the like from a support extending between a pair of spaced ceiling joists and the like.
Interjoist hanger supports are well known in the art for supporting the weight of a fan or lighting fixture and the like between a pair of ceiling joists. Frequently, such supports are installed above a ceiling and between floors of a multi-story structure. In such situations, a standard electrical outlet box cannot be directly mounted to a ceiling and support a significant load, such as that presented by a ceiling fan which may have a weight on the order of 10 pounds to 65 pounds. Instead, an interjoist hanger support is mounted between the floors of a multi-story structure and extends transversely between a pair of ceiling joists above a hole placed in the ceiling. Thereafter, an electrical outlet box may be suspended from the support and which, in turn, will support the fan or other relatively heavy fixture, such as a light fixture and the like.
Examples of prior art interjoist hanger supports include those described in the K. H. Reiker U.S. Pat. No. 4,463,923 and J. R. Kerr U.S. Pat. No. 4,909,405.
The hanger support disclosed in the Reiker patent includes two telescopically extensible members which are in threaded engagement with each other so that the members are movable between a fully collapsed condition and a fully extended condition by rotating the members relative to each other. The free ends of the telescopically extensible members carry prongs which are driven into opposing surfaces of a pair of ceiling joists and are held in place by exerted jack screw forces as the members are extended toward their fully extended length. Reiker also provides spacers fixed to the free ends of the extensible members which engage the upper surface of a ceiling so that the hanger support extends parallel to the ceiling and is spaced therefrom by a fixed distance, on the order of two inches.
One of the problems of employing an interjoist hanger support constructed as illustrated in the Reiker patent involves the amount of time required to install such a hanger support. Typically, such an interjoist hanger support is supplied by the manufacturer in its collapsed condition in which the support has an overall length on the order of fourteen inches. If the ceiling joists are spaced by a distance on the order of twenty-four inches, then the hanger support must be extended substantially before it can be installed in place between a pair of ceiling joists. Because of the threaded connection between the two telescopically extensible members, a substantial amount of time is required by an installer to extend the members prior to positioning the spacer so that it extends transversely between a pair of spaced apart ceiling joists and then further extended by rotational forces to cause the joist engaging prongs or the like on the free ends of the extensible members to be driven into the spaced apart ceiling joists.
A still further problem in using an interjoist hanger support such as disclosed in the Reiker patent is that, when the extensible members are in their fully extended condition, there is a tendency for the center part of the support to sag somewhat toward the upper surface of the ceiling. This results in a tendency for the joist engaging prongs or the like mounted on the free ends of the extendible members to become loose and to disengage from the ceiling joists. The spacers extending from the free ends of the hanger support in the Reiker patent are not adjustable in an axial direction to distribute some of the load to a portion of the ceiling closer to the center of the spacer which would relieve the tendency for the spacer to sag and for the end prongs to disengage from the ceiling joists.
The Kerr patent employs a pair of telescopically extensible members which are axially slidable relative to each other and are not in threaded engagement. Thus, while the two members may be rapidly displaced in an axial direction from a collapsed condition to a fully extended condition, there is no threaded engagement between the members to achieve the jack screw forces provided by the hanger support disclosed in the Reiker patent. Moreover, when the device disclosed in the Kerr patent is in its fully extended position, it will have a tendency to sag somewhat because, like that in the Reiker patent, the device disclosed in the Kerr patent employs spacers that are mounted to the free ends of the extensible members and the spacers are not axially movable so that the load may be shifted somewhat toward the center portion of the hanger support.
A still further problem in employing an interjoist hanger support such as that disclosed in the Kerr patent relates to the difficulty in mounting an electrical outlet box so as to be suspended from the hanger support. This is particularly difficult when this is attempted with one hand extended up through an opening in a ceiling. Thus, when employing a device as described in the Kerr patent, the hanger support is interconnected between a pair of spaced apart ceiling joists above an opening in the ceiling. Then with one hand an electrical outlet box is attached to the mid portion of the hanger support. This is accomplished by attaching a saddle bracket over the hanger support with the saddle bracket having a pair of outwardly extending flanges having mounting apertures therein. An electrical junction box is then mounted to the flanges with screws and nuts. This presents substantial difficulty, as the screws, which are mounted in the apertures in the saddle flanges, tend to become dislodged while attempting to secure the outlet box in place by means of nuts to be threaded onto the threaded portion of the screws.